Re: [RFC] ARM64, PCIe, annd ACPI

[Ray Jui <ray.jui@broadcom.com>]

Hi Lorenzo,

On 8/9/2018 9:00 AM, Lorenzo Pieralisi wrote:
> On Thu, Aug 09, 2018 at 08:44:34AM -0700, Ray Jui wrote:
>> Hi Lorenzo,
>>
>> On 8/9/2018 8:41 AM, Lorenzo Pieralisi wrote:
>>> On Thu, Aug 09, 2018 at 07:57:52AM -0700, Ray Jui wrote:
>>>
>>> [...]
>>>
>>>>> As I said ARM64 ACPI PCI kernel support is in the mainline today and I
>>>>> am not willing to merge any more MCFG quirks at driver level - the
>>>>> information is out there, it is public and must be followed, either
>>>>> designers do that or no ACPI PCI support on your platform, sorry.
>>>>>
>>>>> Lorenzo
>>>>>
>>>>
>>>> I just want to make sure I interpret this properly. This means if
>>>> the PCIe controller hardware does not support ECAM, there's pretty
>>>> much no way around it with SW based workaround going forward with
>>>> mainline kernel?
>>>
>>> Yes.
>>>
>>>> What about for the PCIe controller that was designed a few years back?
>>>
>>> It will bootstrap with DT :)
>>
>> Okay, one more quick question, what about for distributions that
>> will eventually disable DT and force ACPI?
> 
> ACPI PCI support revolves around a FW model that requires, among other
> things, ECAM and its firmware description, MCFG table, to work.
> 
> If the host controller is not ECAM compliant it is not PCI firmware
> compliant, so it is not ACPI compliant, you can't run ACPI only
> distributions on it.
> 
> It is a model that has been run for decades in basically all
> ACPI based systems out there and there is not a reason to
> deviate from it, I understand the frustration but that's the
> way it is, sorry.
> 
> Thanks,
> Lorenzo
> 

Okay that draws the line. Thanks for confirming.

Ray